/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.jena.sparql.engine.iterator;

import org.apache.jena.query.QueryCancelledException;
import org.apache.jena.query.QueryExecException;
import org.apache.jena.sparql.engine.ExecutionContext;
import org.apache.jena.sparql.engine.QueryIterator;
import org.apache.jena.sparql.engine.binding.Binding;

/**
 * A helper iterator for when an intermediate step in the construction of a compound iterator fails.
 */
public class QueryIterFailed
    extends QueryIter1
{
    private Throwable cause;

    public QueryIterFailed(QueryIterator input, ExecutionContext execCxt, Throwable cause) {
        super(input, execCxt);
        this.cause = cause;
    }

    @Override
    protected void requestSubCancel() {
    }

    @Override
    protected void closeSubIterator() {
    }

    @Override
    protected boolean hasNextBinding() {
        throw buildException();
    }

    @Override
    protected Binding moveToNextBinding() {
        throw buildException();
    }

    protected QueryExecException buildException() {
        if (cause instanceof QueryCancelledException e) {
            return new QueryCancelledException(e);
        } else {
            return new QueryExecException(cause);
        }
    }
}
